<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
	</body>
	<script type="text/javascript">
		var a=1;
		while(a<=100){
			var b=a+1;
			var c=a+b;
			a=a+1;			
		}
		document.write("1+2+3...+100的值为："+c)
	</script>
</html>